干湿循环作用下岸坡消落带土体抗剪强度劣化规律及其对岸坡稳定性影响研究

发布时间：2018-05-12 05:40

本文选题：岸坡 + 消落带　；参考：《岩土力学》2017年09期

【摘要】：三峡水库蓄水运行之后,库水位每年都在145 m的防洪水位和175 m的蓄水发电水位之间或缓慢或快速地升降变化,岸坡消落带区域岩土体长期处于干湿循环状态,其力学参数的劣化规律将直接影响岸坡的变形稳定。基于此,设计并进行了典型岸坡消落带土体的干湿循环作用试验。结果表明:(1)在干湿循环作用过程中,土体抗剪强度参数劣化幅度非常明显,其中,前4次干湿循环作用导致的抗剪强度参数劣化幅度占总劣化度的75%左右,4次干湿循环作用之后,劣化趋势逐渐趋于平缓;(2)在干湿循环作用下,土样内部的微观裂纹、裂隙反复张开闭合,逐渐发育、汇集,土样由密实状态逐渐变为内部裂纹发育的松散状态,土样内部的损伤是导致其抗剪强度参数逐渐劣化的根本原因;(3)考虑干湿循环作用下消落带土体参数劣化时,岸坡消落带区域局部安全系数劣化趋势明显,总体趋势与消落带土体抗剪强度参数劣化规律一致,而且岸坡消落带区域附近的局部滑动迹象明显,这与现场踏勘所见到的该区域明显发育的裂缝、下挫现象是一致的。研究成果对库水作用下岸坡的长期变形稳定评价具有较大的参考意义,相关分析方法也可以为类似试验提供参考。
[Abstract]:After the operation of the three Gorges Reservoir, the water level of the reservoir changes slowly or rapidly between the flood control water level of 145 m and the water level of water storage and power generation at 175 m each year, and the rock and soil in the area of bank slope drop zone are in the state of dry and wet circulation for a long time. The deterioration of mechanical parameters will directly affect the deformation stability of bank slope. Based on this, the dry and wet circulation tests of the soil in the typical bank slope collapse zone are designed and carried out. The results show that in the process of dry-wet circulation, the deterioration of shear strength parameters of soil is very obvious, among which, The degradation range of shear strength parameters caused by the first four dry-wet cycles accounts for about 75% of the total deterioration. After 4 cycles, the deterioration trend gradually tends to be gentle.) under the action of dry and wet cycles, the micro-cracks in the soil samples, The cracks were repeatedly opened and closed, gradually developed and collected, and the soil samples gradually changed from a dense state to a loose state of internal crack development. The internal damage of soil sample is the fundamental reason for the gradual deterioration of shear strength parameters. The general trend is consistent with the deterioration rule of soil shear strength parameters in the subsidence zone, and the signs of local sliding near the landslide zone are obvious, which is consistent with the obvious cracks developed in this area and the decline phenomenon seen in the field survey. The research results have great reference significance for the long-term deformation stability evaluation of bank slope under the action of reservoir water, and the related analysis method can also provide reference for similar tests.
【作者单位】：三峡大学三峡库区地质灾害教育部重点实验室;
【基金】：湖北省自然科学基金重点项目(No.2015CFA140) 国家自然科学基金重点项目(No.51439003);国家自然科学基金资助项目(No.51679127)~~
【分类号】：TV223;TV697

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